Stimulating targeting needle

Abstract

A surgical system may include a conductive stylet with a distal end advanceable into bone material and a proximal end coupled to a stylet hub. A handle is non-removably attached to the stylet hub, and removably attachable to an insulative cannula hub. The cannula hub is non-removably attached to a conductive cannula that surrounds the stylet when the handle is attached to the proximal end of the insulative cannula hub. An outer insulative sheath is slideably engaged to insulative cannula hub, and has a radiopaque distal tip. An electrical signal source may be applied to the stylet hub to conduct a pedicle integrity assessment. The handle and stylet may be removed from the cannula assembly, leaving the cannula assembly in place at the surgical site.

What is claimed: 
     
       1. A surgical tool system comprising:
 a conductive stylet comprising a shaft extending from a distal end to a proximal end, the distal end advanceable into bone material, and the proximal end receivable within a conductive stylet hub; 
 a handle non-removably attached to the conductive stylet hub, the handle comprising a proximal gripping portion, and the handle removably attachable to a proximal end of an insulative cannula hub, wherein when the handle is removed from the proximal end of the insulative cannula hub, the conductive stylet hub is also removed; 
 the insulative cannula hub non-removably attached to a conductive cannula; 
 the conductive cannula surrounding the conductive stylet when the handle is attached to the proximal end of the insulative cannula hub; and 
 an outer, elongated insulative sheath slideably engaged to insulative cannula hub, the outer, elongated insulative sheath further comprising a tip on a distal end formed of radiopaque material. 
 
     
     
       2. The surgical tool system of  claim 1 , the conductive stylet hub comprising a stylet hub diameter, and the conductive cannula comprising a cannula diameter, the stylet hub diameter being at least as large as the cannula diameter. 
     
     
       3. The surgical tool system of  claim 1 , the conductive cannula surrounding the conductive stylet when the insulative cannula hub is attached to the handle. 
     
     
       4. The surgical tool system of  claim 1 , the handle further comprising a distal connecting portion, the conductive stylet hub receivable within a longitudinal void extending through the proximal gripping portion and distal connecting portion. 
     
     
       5. The surgical tool system of  claim 4 , the handle further comprising a projection on the distal connecting portion, the projection comprising a laterally extending flange; and the insulative cannula hub comprising a proximal void and one or more slots, the projection on the distal connecting portion of the handle receivable within the proximal void and the laterally extending flange receivable within the one or more slots. 
     
     
       6. The surgical tool system of  claim 1 , wherein the conductive stylet is integral to the handle. 
     
     
       7. The surgical tool system of  claim 1 , wherein the outer, elongated insulative sheath comprises a front half and a back half, the front half and back half ultrasonically welded together along a longitudinal axis of the outer, elongated insulative sheath. 
     
     
       8. The surgical tool system of  claim 1 , wherein the conductive cannula comprises a proximal diameter tapering to a distal diameter, the distal diameter smaller than the proximal diameter. 
     
     
       9. The surgical tool system of  claim 1 , wherein the conductive stylet further comprises a geometry at its distal tip, and the handle further comprises a geometry indicator at a proximal end of the handle. 
     
     
       10. The surgical tool system of  claim 1 , wherein the conductive stylet hub surrounds the proximal end of the conductive stylet. 
     
     
       11. The surgical tool system of  claim 1 , wherein the handle further comprises a proximal end and a distal end, with a void extending longitudinally through the proximal end and the distal end, the conductive stylet hub passing through the void in the proximal end and distal end. 
     
     
       12. The surgical tool system of  claim 11 , wherein a proximal end of the conductive stylet hub is exposed through the proximal end of the handle. 
     
     
       13. The surgical tool system of  claim 1 , the insulative cannula hub further comprising markings indicating a length of the conductive stylet extending beyond the outer, elongated insulative sheath. 
     
     
       14. The surgical tool system of  claim 1 , the elongated insulative sheath further comprising markings indicating a depth of penetration of the surgical tool system. 
     
     
       15. The surgical tool system of  claim 1 , the insulative cannula hub further comprising a longitudinal channel having a first groove and a second groove, and the outer, elongated insulative sheath further comprising an extension slideable within the longitudinal channel. 
     
     
       16. The surgical tool system of  claim 1 , the conductive stylet hub coupleable to an electrical source to transmit an electrical current from the electrical source to the conductive stylet hub. 
     
     
       17. The surgical tool system of  claim 1 , wherein the conductive cannula is comprised of entirely conductive material. 
     
     
       18. The surgical tool system of  claim 1 , wherein an electrical source is connectable to the conductive stylet hub when the handle is removably attached to the proximal end of an insulative cannula hub, the electrical source to conduct electricity from the electrical source, through the conductive stylet hub to the conductive stylet and conductive cannula, and wherein the electrical source cannot be connected to the conductive stylet hub to conduct electricity from the electrical source through the conductive cannula when the handle is removed from the proximal end of the insulative cannula hub. 
     
     
       19. The surgical tool system of  claim 1 , wherein the handle has a first position attached to the proximal end of the insulative cannula hub, and a second position wherein the handle is removed from the proximal end of the insulative cannula hub; and
 wherein, in the first position, an electrical source if coupled to the conductive stylet hub can conduct electricity through the conductive cannula, and in the second position the electrical source if coupled to the conductive stylet hub cannot conduct electricity through the conductive cannula.